启动时 Java 代理死锁，锁定 ClassLoader 和 [I?

编程问答 2022-05-10

问题描述

具有两个 javaagent 的应用程序，陷入死锁（在 main 执行之前）。

为什么有一个线程试图获取 [I 的锁？为什么会有死杯？

jstack 的死锁输出：

Found one Java-level deadlock:
=============================
"com.taobao.diamond.client.Worker.longPullingdefault":
  waiting to lock monitor 0x00007fb6341d0ec8 (object 0x000000073e8efe20,a [I),which is held by "oneagent plugin Bsnt-agent start"
"oneagent plugin Bsnt-agent start":
  waiting to lock monitor 0x00007fb6940038d8 (object 0x0000000766224ec8,a com.bilibili.ntib.agent.starter.SandBoxClassLoader),which is held by "oneagent plugin msha-java-agent start"
"oneagent plugin msha-java-agent start":
  waiting to lock monitor 0x00007fb6341d0ec8 (object 0x000000073e8efe20,which is held by "oneagent plugin Bsnt-agent start"

Java stack information for the threads listed above:
===================================================
"com.taobao.diamond.client.Worker.longPullingdefault":
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.structure.ClassstructureImplByAsm.<init>(ClassstructureImplByAsm.java:400)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.structure.ClassstructureFactory.createClassstructure(ClassstructureFactory.java:57)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.SandBoxClassFileTransformer.getClassstructure(SandBoxClassFileTransformer.java:64)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.SandBoxClassFileTransformer._transform(SandBoxClassFileTransformer.java:117)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.SandBoxClassFileTransformer.transform(SandBoxClassFileTransformer.java:84)
    at sun.instrument.TransformerManager.transform(TransformerManager.java:188)
    at sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:428)
    at java.lang.classLoader.defineClass1(Native Method)
    at java.lang.classLoader.defineClass(ClassLoader.java:763)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.urlclassloader.defineClass(urlclassloader.java:467)
    at java.net.urlclassloader.access$100(urlclassloader.java:73)
    at java.net.urlclassloader$1.run(urlclassloader.java:368)
    at java.net.urlclassloader$1.run(urlclassloader.java:362)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.urlclassloader.findClass(urlclassloader.java:361)
    at java.lang.classLoader.loadClass(ClassLoader.java:424)
    - locked <0x00000007435e1620> (a java.lang.Object)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
    at java.lang.classLoader.loadClass(ClassLoader.java:357)
    at com.taobao.diamond.client.impl.CacheData.safeNotifyListener(CacheData.java:145)
    at com.taobao.diamond.client.impl.CacheData.checkListenerMd5(CacheData.java:136)
    at com.taobao.diamond.client.impl.ClientWorker$LongPullingRunnable.run(ClientWorker.java:451)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
"oneagent plugin Bsnt-agent start":
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.structure.ClassstructureImplByAsm.<init>(ClassstructureImplByAsm.java:400)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.structure.ClassstructureFactory.createClassstructure(ClassstructureFactory.java:57)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.SandBoxClassFileTransformer.getClassstructure(SandBoxClassFileTransformer.java:64)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.SandBoxClassFileTransformer._transform(SandBoxClassFileTransformer.java:117)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.SandBoxClassFileTransformer.transform(SandBoxClassFileTransformer.java:84)
    at sun.instrument.TransformerManager.transform(TransformerManager.java:188)
    at sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:428)
    at java.lang.classLoader.defineClass1(Native Method)
    at java.lang.classLoader.defineClass(ClassLoader.java:763)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.urlclassloader.defineClass(urlclassloader.java:467)
    at java.net.urlclassloader.access$100(urlclassloader.java:73)
    at java.net.urlclassloader$1.run(urlclassloader.java:368)
    at java.net.urlclassloader$1.run(urlclassloader.java:362)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.urlclassloader.findClass(urlclassloader.java:361)
    at java.lang.classLoader.loadClass(ClassLoader.java:424)
    - locked <0x000000073e463248> (a com.navercorp.pinpoint.common.plugin.PluginLoaderClassLoader)
    at com.navercorp.pinpoint.common.plugin.PluginLoaderClassLoader.loadClass(PluginLoaderClassLoader.java:45)
    - locked <0x000000073e463248> (a com.navercorp.pinpoint.common.plugin.PluginLoaderClassLoader)
    at java.lang.classLoader.loadClass(ClassLoader.java:357)
    at com.navercorp.pinpoint.plugin.jdbc.ppas.PPASPlugin.<init>(PPASPlugin.java:29)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at java.lang.class.newInstance(Class.java:442)
    at java.util.ServiceLoader$LazyIterator.nextService(ServiceLoader.java:380)
    at java.util.ServiceLoader$LazyIterator.next(ServiceLoader.java:404)
    at java.util.ServiceLoader$1.next(ServiceLoader.java:480)
    at com.navercorp.pinpoint.common.plugin.PluginLoader.load(PluginLoader.java:66)
    at com.navercorp.pinpoint.common.plugin.PluginLoader.load(PluginLoader.java:47)
    at com.navercorp.pinpoint.profiler.plugin.ProfilerPluginLoader.load(ProfilerPluginLoader.java:84)
    at com.navercorp.pinpoint.profiler.plugin.DefaultPluginContextLoadResult.load(DefaultPluginContextLoadResult.java:80)
    at com.navercorp.pinpoint.profiler.plugin.DefaultPluginContextLoadResult.<init>(DefaultPluginContextLoadResult.java:70)
    at com.navercorp.pinpoint.profiler.context.provider.PluginContextLoadResultProvider.get(PluginContextLoadResultProvider.java:68)
    at com.navercorp.pinpoint.profiler.context.provider.PluginContextLoadResultProvider.get(PluginContextLoadResultProvider.java:34)
    at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:81)
    at com.google.inject.internal.BoundProviderFactory.provision(BoundProviderFactory.java:72)
    at com.google.inject.internal.ProviderInternalFactory.circularGet(ProviderInternalFactory.java:61)
    at com.google.inject.internal.BoundProviderFactory.get(BoundProviderFactory.java:62)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter$1.call(ProviderToInternalFactoryAdapter.java:46)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1092)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
    at com.google.inject.internal.SingletonScope$1.get(SingletonScope.java:194)
    at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:41)
    at com.google.inject.internal.InjectorImpl$2$1.call(InjectorImpl.java:1019)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1092)
    at com.google.inject.internal.InjectorImpl$2.get(InjectorImpl.java:1015)
    at com.navercorp.pinpoint.profiler.context.provider.ApplicationServerTypeProvider.get(ApplicationServerTypeProvider.java:62)
    at com.navercorp.pinpoint.profiler.context.provider.ApplicationServerTypeProvider.get(ApplicationServerTypeProvider.java:36)
    at com.google.inject.internal.ProviderInternalFactory.provision(ProviderInternalFactory.java:81)
    at com.google.inject.internal.BoundProviderFactory.provision(BoundProviderFactory.java:72)
    at com.google.inject.internal.ProviderInternalFactory.circularGet(ProviderInternalFactory.java:61)
    at com.google.inject.internal.BoundProviderFactory.get(BoundProviderFactory.java:62)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter$1.call(ProviderToInternalFactoryAdapter.java:46)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1092)
    at com.google.inject.internal.ProviderToInternalFactoryAdapter.get(ProviderToInternalFactoryAdapter.java:40)
    at com.google.inject.internal.SingletonScope$1.get(SingletonScope.java:194)
    at com.google.inject.internal.InternalFactoryToProviderAdapter.get(InternalFactoryToProviderAdapter.java:41)
    at com.google.inject.internal.InternalInjectorCreator$1.call(InternalInjectorCreator.java:205)
    at com.google.inject.internal.InternalInjectorCreator$1.call(InternalInjectorCreator.java:199)
    at com.google.inject.internal.InjectorImpl.callInContext(InjectorImpl.java:1085)
    at com.google.inject.internal.InternalInjectorCreator.loadEagerSingletons(InternalInjectorCreator.java:199)
    at com.google.inject.internal.InternalInjectorCreator.injectDynamically(InternalInjectorCreator.java:180)
    at com.google.inject.internal.InternalInjectorCreator.build(InternalInjectorCreator.java:110)
    at com.google.inject.Guice.createInjector(Guice.java:99)
    at com.google.inject.Guice.createInjector(Guice.java:84)
    at com.navercorp.pinpoint.profiler.context.module.DefaultApplicationContext.<init>(DefaultApplicationContext.java:145)
    at com.navercorp.pinpoint.profiler.DefaultAgent.newApplicationContext(DefaultAgent.java:127)
    at com.navercorp.pinpoint.profiler.DefaultAgent.<init>(DefaultAgent.java:107)
    at com.navercorp.pinpoint.profiler.DefaultAgent.<init>(DefaultAgent.java:70)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
    at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
    at com.navercorp.pinpoint.bootstrap.AgentClassLoader$2.call(AgentClassLoader.java:78)
    at com.navercorp.pinpoint.bootstrap.ContextClassLoaderExecuteTemplate.execute(ContextClassLoaderExecuteTemplate.java:42)
    at com.navercorp.pinpoint.bootstrap.AgentClassLoader.boot(AgentClassLoader.java:73)
    at com.navercorp.pinpoint.bootstrap.PinpointStarter.run(PinpointStarter.java:111)
    at com.navercorp.pinpoint.bootstrap.PinpointBootStrap.bootstrap(PinpointBootStrap.java:255)
    at com.navercorp.pinpoint.bootstrap.PinpointBootStrap.premain(PinpointBootStrap.java:40)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.alibaba.oneagent.plugin.TraditionalPlugin.start(TraditionalPlugin.java:109)
    at com.alibaba.oneagent.plugin.PluginManagerImpl.startOnePlugin(PluginManagerImpl.java:302)
    at com.alibaba.oneagent.plugin.PluginManagerImpl.access$200(PluginManagerImpl.java:31)
    at com.alibaba.oneagent.plugin.PluginManagerImpl$2.run(PluginManagerImpl.java:333)
    at java.lang.Thread.run(Thread.java:748)
"oneagent plugin msha-java-agent start":
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.structure.ClassstructureImplByAsm.<init>(ClassstructureImplByAsm.java:400)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.structure.ClassstructureFactory.createClassstructure(ClassstructureFactory.java:57)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.SandBoxClassFileTransformer.getClassstructure(SandBoxClassFileTransformer.java:64)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.SandBoxClassFileTransformer._transform(SandBoxClassFileTransformer.java:117)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.SandBoxClassFileTransformer.transform(SandBoxClassFileTransformer.java:84)
    at sun.instrument.TransformerManager.transform(TransformerManager.java:188)
    at sun.instrument.InstrumentationImpl.transform(InstrumentationImpl.java:428)
    at java.lang.classLoader.defineClass1(Native Method)
    at java.lang.classLoader.defineClass(ClassLoader.java:763)
    at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
    at java.net.urlclassloader.defineClass(urlclassloader.java:467)
    at java.net.urlclassloader.access$100(urlclassloader.java:73)
    at java.net.urlclassloader$1.run(urlclassloader.java:368)
    at java.net.urlclassloader$1.run(urlclassloader.java:362)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.urlclassloader.findClass(urlclassloader.java:361)
    at java.lang.classLoader.loadClass(ClassLoader.java:424)
    - locked <0x000000073e0a65f8> (a java.lang.Object)
    at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:349)
    at java.lang.classLoader.loadClass(ClassLoader.java:411)
    - locked <0x0000000766224ec8> (a com.bilibili.ntib.agent.starter.SandBoxClassLoader)
    at java.lang.classLoader.loadClass(ClassLoader.java:357)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.classloader.Routingurlclassloader$1.loadClass(Routingurlclassloader.java:74)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.classloader.ClassLoadingLock.loadingInLock(ClassLoadingLock.java:55)
    - locked <0x000000073e0a5610> (a java.lang.Object)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.classloader.Routingurlclassloader.loadClass(Routingurlclassloader.java:63)
    at java.lang.classLoader.loadClass(ClassLoader.java:357)
    at com.bilibili.ntib.agent.sandBox.module.SandBoxFilter.doClassFilter(SandBoxFilter.java:97)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.ExtFilterMatcher.matchingClassstructure(ExtFilterMatcher.java:59)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.ExtFilterMatcher._matching(ExtFilterMatcher.java:113)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.ExtFilterMatcher.matching(ExtFilterMatcher.java:79)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.matcher.GroupMatcher$And.matching(GroupMatcher.java:52)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreLoadedClassDataSource.find(DefaultCoreLoadedClassDataSource.java:106)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreLoadedClassDataSource.findForReTransform(DefaultCoreLoadedClassDataSource.java:73)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultModuleEventWatcher.watch(DefaultModuleEventWatcher.java:186)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultModuleEventWatcher.watch(DefaultModuleEventWatcher.java:158)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultModuleEventWatcher.watch(DefaultModuleEventWatcher.java:150)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.util.SandBoxProtector$2.invoke(SandBoxProtector.java:91)
    at com.sun.proxy.$Proxy56.watch(UnkNown Source)
    at com.bilibili.ntib.agent.sandBox.module.MshaSandBoxModule.registeraspectPlugins(MshaSandBoxModule.java:123)
    at com.bilibili.ntib.agent.sandBox.module.MshaSandBoxModule.loadAspectPlugins(MshaSandBoxModule.java:55)
    at com.bilibili.ntib.agent.sandBox.module.MshaSandBoxModule.onActive(MshaSandBoxModule.java:44)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager.callAndFireModuleLifeCycle(DefaultCoreModuleManager.java:120)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager.active(DefaultCoreModuleManager.java:433)
    - locked <0x0000000737424d18> (a com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager.markActiveOnLoadIfNecessary(DefaultCoreModuleManager.java:338)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager.load(DefaultCoreModuleManager.java:193)
    - locked <0x0000000737424d18> (a com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager.access$300(DefaultCoreModuleManager.java:38)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager$InnerModuleLoadCallback.onLoad(DefaultCoreModuleManager.java:580)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.ModuleJarLoader.loadingModules(ModuleJarLoader.java:93)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.ModuleJarLoader.load(ModuleJarLoader.java:129)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.ModuleLibLoader.load(ModuleLibLoader.java:77)
    at com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager.reset(DefaultCoreModuleManager.java:607)
    - locked <0x0000000737424d18> (a com.bilibili.ntib.third.com.alibaba.jvm.sandBox.core.manager.impl.DefaultCoreModuleManager)
    at com.bilibili.ntib.agent.boot.sandBox.AgentModuleManager.initManager(AgentModuleManager.java:120)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.bilibili.ntib.agent.starter.initializer.SandBoxAgentinitializer.init(SandBoxAgentinitializer.java:18)
    at com.bilibili.ntib.agent.starter.AgentLauncher.launch(AgentLauncher.java:53)
    at com.bilibili.ntib.agent.starter.AgentMain.premain(AgentMain.java:24)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at com.alibaba.oneagent.plugin.TraditionalPlugin.start(TraditionalPlugin.java:109)
    at com.alibaba.oneagent.plugin.PluginManagerImpl.startOnePlugin(PluginManagerImpl.java:302)
    at com.alibaba.oneagent.plugin.PluginManagerImpl.access$200(PluginManagerImpl.java:31)
    at com.alibaba.oneagent.plugin.PluginManagerImpl$2.run(PluginManagerImpl.java:333)
    at java.lang.Thread.run(Thread.java:748)

Found 1 deadlock.

jstack 的完整输出：https://pastebin.com/z1frQepX

jstack -m 的完整输出：https://pastebin.com/t6aWE6K7

一些真实的源代码：

class SandBoxClassLoader extends urlclassloader {

    SandBoxClassLoader(final String namespace) throws Throwable {
        super(getServiceJar());
    }

    private static URL[] getServiceJar() throws IOException {
        // ...
        return urls;
    }

    @Override
    public URL getResource(String name) {
        URL url = super.getResource(name);
        return url;
    }

    @Override
    public Enumeration<URL> getResources(String name) throws IOException {
        Enumeration<URL> urls = super.getResources(name);
        return urls;
    }
}

Java 版本：Java HotSpot(TM) 64-Bit Server VM; 1.8.0_172; 25.172-b11; mixed mode

解决方法

查看 jstack 输出，我们看到以下内容：

  1. com.taobao.diamond.client.Worker.longPullingdefault 的调用堆栈：

    • ClassStructureImplByAsm.<init>(ClassStructureImplByAsm.java:400)：<init> 告诉您在执行构造函数或以其他方式初始化正在构造的对象的实例时发生了某些事情，即在为字段分配默认值时。后者是这里的情况，因为第 400 行为 ClassStructureImplByAsm.annotationTypeClassStructuresLazyGet 类型的 LazyGet 分配了一个值。更准确地说，正在创建和分配匿名 LazyGet<List<ClassStructure>> 子类的实例。

    • 往下看第一个调用堆栈，我们看到 CacheData.safeNotifyListener 试图调用 ClassLoader.loadClass。在 JDK 源代码中该方法的开头，您会看到 synchronized (getClassLoadingLock(name))，而在 getClassLoadingLock 中，您会看到默认情况下（非并行类加载器）它只是在 this 上同步，即类加载器实例。

  2. oneagent plugin Bsnt-agent start 的调用堆栈：

    • 同样，调用堆栈的顶部是 ClassStructureImplByAsm.<init>(ClassStructureImplByAsm.java:400)，就像以前一样。

    • 再次触发 ClassLoader.loadClass 并在类加载器上同步，这次由 PluginLoaderClassLoader.loadClass(PluginLoaderClassLoader.java:45) 调用。

  3. oneagent plugin msha-java-agent start 的调用堆栈：

    • 同样，调用堆栈的顶部是 ClassStructureImplByAsm.<init>(ClassStructureImplByAsm.java:400)，就像以前一样。

    • 再次，ClassLoader.loadClass 被触发并在类加载器上同步，这次由 SandboxFilter.doClassFilter(SandboxFilter.java:97) 间接调用，通过 RoutingURLClassLoader$1.loadClass(RoutingURLClassLoader.java:74) 进一步调用堆栈。 SandboxClassLoader 似乎也参与其中。

我不确定，但看起来死锁以某种方式发生在 ClassLoader 基类中，而三个单独的线程正试图同时对其进行同步。

也许在惰性 getter 方法中延迟分配 ClassStructureImplByAsm.annotationTypeClassStructuresLazyGet 会有所帮助，即当第一次需要成员并且仍然 null 时，getter 创建匿名子类实例。否则它只返回已经分配的成员。我不知道您是否是 ClassStructureImplByAsm 的维护者并且可以更改它，但即使不是，您至少可以在为上游项目创建拉取请求之前将其分叉并在本地测试修改。

抱歉，我不能说任何更具体的内容，因为我无法编译和运行 jstack 协议来重现您的问题。复制器示例项目，即 MCVE，本来会更好。

deadlockdeadlockjavajavajavaagentsmultithreadingmultithreading